Therapy strategies of fifth metatarsal base fracture with lateral collateral ligament injury.

Background: Fifth metatarsal base fracture (fifth MBF) and lateral collateral ankle ligament (LCAL) injury are mainly caused by plantar flexion and inversion of the foot. However, there is no relevant report on the incidence, injury type and treatment principle of the fifth MBF combined with an LCAL injury.

Materials And Methods: We retrospectively analyzed 61 patients with fifth MBF. After admission, patients were given the symptomatic treatment and underwent standard anteroposterior (AP), 30-degree oblique foot radiographs, ankle MR and/or ultrasonic examination. The type of surgery varied base on the individual patients (type of fracture with/without lateral collateral ankle ligament injury).

Results: In 61 patients, there were 39 patients with LCAL injury. Among the 39 patients with LCAL injury, 24 patients with Grade I-II injury, 6 patients with Grade III injury, and 9 patients with avulsion fractures. There was no significant difference between the patients without LCAL injury and the patients with LCAL injury in terms of age (p = 0.67) and gender (p = 0.575). The incidence of fifth MBF with LCAL injury accounted for 63.93% of fifth metatarsal base fracture; the most common causes of injury included sprains and falls. The average fracture healing time was 8.3 (range, 6-12) weeks. For fifth MBF with displaced more than 2 mm, hook plate or lag screw was used for fixation; for complete rupture of LCAL, suture anchor was used to repairing the ligament; for partial LCAL injury, plaster was used for fixation after surgery; for avulsion fractures, cannulated screw or suture anchor was used for repair. None of the patients had complications such as delayed union, nonunion, and incision infection.

Conclusion: Early diagnosis and appropriate treatment can obtain good therapeutic results in fifth MBF patients combined with LCAL injury. Moreover, defining a treatment plan for ligament injury is essential for reducing postoperative complications. This study provides a basis for epidemiology, diagnosis, and treatment of fifth MBF with LCAL injury.